Semiconductor arrangement and formation thereof

ABSTRACT

A semiconductor arrangement and method of formation are provided. The semiconductor arrangement includes an interconnect which includes an interconnect metal plug surrounded by a second metal layer. The interconnect is adjacent a sidewall of a dielectric, such that an air gap is between the interconnect and the sidewall of the dielectric. A protective barrier is over the interconnect and the air gap, and is over and in direct physical contact with a top surface of the dielectric. The interconnect metal plug surrounded by the second metal layer is less susceptible to damage than an interconnect metal plug that is not surrounded by a second metal layer. The protective barrier in direct physical contact with the dielectric reduces parasitic capacitance, which reduces an RC delay of the semiconductor arrangement, as compared to a semiconductor arrangement that does not have a protective barrier in direct physical contact with a dielectric.

BACKGROUND

A semiconductor arrangement comprises one or more contacts. Contacts areused to make electrical connections in or among different features in asemiconductor arrangement. A contact, for example, is used to connectone metal layer to another metal layer, where the metal layers areotherwise electrically isolated from one another, such as by aninsulating or dielectric material separating the metal layers.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a flow diagram illustrating a method of forming asemiconductor arrangement, in accordance with some embodiments.

FIG. 2 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 3 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 4 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 5 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 6 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 7 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 8 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 9 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

FIG. 10 is an illustration of a semiconductor arrangement, in accordancewith some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

One or more techniques for forming a semiconductor arrangement andresulting structures formed thereby are provided herein.

A method 100 of forming a semiconductor arrangement 200 according tosome embodiments is illustrated in FIG. 1 and one or more structuresformed thereby at various stages of fabrication are illustrated in FIGS.2-10. In some embodiments, as illustrated in FIG. 10, the semiconductorarrangement 200 comprises a first interconnect 228 a adjacent a secondinterconnect 228 b. In some embodiments, the first interconnect 228 a isover a first bottom portion 204 a 3 of a first metal layer 204. In someembodiments, the first metal layer 204, illustrated in FIG. 6, comprisestitanium nitride. In some embodiments, the second interconnect 228 b isover a second bottom portion 204 b 3 of the first metal layer 204, asillustrated in FIG. 10. In some embodiments, at least one of the firstbottom portion 204 a 3 or the second bottom portion 204 b 3 is incontact with a dielectric 202. In some embodiments, the firstinterconnect 228 a comprises a first interconnect metal plug 210 a, afirst interconnect second metal layer 208 a and a first barrier cap 212a. In some embodiments, the first barrier cap 212 a is over a topsurface of the first interconnect metal plug 210 a. In some embodiments,the first interconnect second metal layer 208 a surrounds a bottomsurface 211 c and sidewalls 211 a, 211 b of the first interconnect metalplug 210 a. In some embodiments, the second interconnect 228 b comprisesa second interconnect metal plug 210 b, a second interconnect secondmetal layer 208 b and a second barrier cap 212 b. In some embodiments,the second barrier cap 212 b is over a top surface of the secondinterconnect metal plug 210 b. In some embodiments, the secondinterconnect second metal layer 208 b surrounds a bottom surface 213 cand sidewalls 213 a, 213 b of the second interconnect metal plug 210 b.In some embodiments, the first interconnect second metal layer 208 a andthe second interconnect second metal layer 208 b are formed from asecond metal layer 208, as illustrated in FIG. 4, the second metal layer208 comprising at least one of tantalum or nitride. In some embodiments,a first air gap 220 a is defined between a first side 223 a of the firstinterconnect 228 a and a first sidewall 202 a of the dielectric 202. Insome embodiments, a second air gap 220 b is defined between a secondside 223 b of the first interconnect 228 a and a first side 225 a of thesecond interconnect 228 b. In some embodiments, a first bottom portionwidth 232 a of the first bottom portion 204 a 3 is substantially equalto a first interconnect width 234 a of the first interconnect 228 a. Insome embodiments, a second bottom portion width 232 b of the secondbottom portion 204 b 3 is substantially equal to a second interconnectwidth 234 b of the second interconnect 228 b. In some embodiments, afirst interconnect first bottom void 230 a 1 is on the first side 223 aof the first interconnect 228 a. In some embodiments, the firstinterconnect first bottom void 230 a 1 is defined between a first bottomsidewall 203 a 1 of the first bottom portion 204 a 3 and a firstinterconnect first void sidewall 202 a 1 of the dielectric 202. In someembodiments, a first interconnect second bottom void 230 a 2 is on thesecond side 223 b of the first interconnect 228 a. In some embodiments,the first interconnect second bottom void 230 a 2 is defined between asecond bottom sidewall 203 a 2 of the first bottom portion 204 a 3 and afirst interconnect second void sidewall 202 a 2 of the dielectric 202.In some embodiments, a second interconnect first bottom void 230 b 1 ison the first side 225 a of the second interconnect 228 b. In someembodiments, the second interconnect first bottom void 230 b 1 isdefined between a first bottom sidewall 203 b 1 of the second bottomportion 204 b 3 and a second interconnect first void sidewall 202 b 1 ofthe dielectric 202. In some embodiments, a second interconnect secondbottom void 230 b 2 is on a second side 225 b of the second interconnect228 b. In some embodiments, the second interconnect second bottom void230 b 2 is defined between a second bottom sidewall 203 b 2 of thesecond bottom portion 204 b 3 and a second interconnect second voidsidewall 202 b 2 of the dielectric 202. In some embodiments, aprotective barrier 218 is over the first interconnect 228 a and thesecond interconnect 228 b. In some embodiments, the protective barrier218 is in direct physical contact with a second top portion 221 a, 221 bof a top surface of the dielectric 202. In some embodiments, a pluralityof interconnects are contemplated, such as a third interconnect 228 c.In some embodiments, an interconnect metal plug 210 surrounded by thesecond metal layer 208 has greater protection and thus is lesssusceptible to damage than an interconnect metal plug that is notsurrounded by a second metal layer. In some embodiments, thesemiconductor arrangement 200 where the protective barrier 218 is indirect physical contact with the dielectric 202 has a reduced parasiticcapacitance as compared to a semiconductor arrangement that does nothave a protective barrier in direct physical contact with a dielectric.In some embodiments, reduced parasitic capacitance reduces an RC delay,such that a semiconductor arrangement with reduced parasitic capacitancehas a reduced RC delay.

Turning to 102 of the method 100, as illustrated in FIG. 3, the firstmetal layer 204 comprising titanium nitride is formed in a first opening206 a in the dielectric 202, a second opening 206 b in the dielectric202, a third opening 206 c in the dielectric 202 and over the dielectric202, according to some embodiments. Turning to FIG. 2, prior to FIG. 3,the first opening 206 a, the second opening 206 b and the third opening206 c are in the dielectric 202. In some embodiments, the dielectric 202comprises at least one of a high dielectric constant material, a mediumdielectric constant material or a low dielectric constant material. Insome embodiments, the dielectric 202 comprises at least one of an oxideor a nitride. Turning to FIG. 3, the first metal layer 204 is formed bydeposition, such as by physical vapor deposition (PVD) or RF PVD. Insome embodiments, the first metal layer 204 has a first metal layerthickness between about 100 Å to about 300 Å.

Turning to 104 of the method 100, as illustrated in FIG. 6, the firstinterconnect 228 a is formed over the first metal layer 204 in the firstopening 206 a, the second interconnect 228 b is formed over the firstmetal layer 204 in the second opening 206 b and the third interconnect228 c is formed over the first metal layer 204 in the third opening 206c, according to some embodiments. Turning to FIG. 4, prior to FIG. 6,the second metal layer 208 is formed over the first metal layer 204. Insome embodiments, the second metal layer 208 is formed by at least oneof PVD, atomic layer deposition (ALD) or chemical vapor deposition(CVD). In some embodiments, the second metal layer 208 has a secondmetal layer thickness between about 20 Å to about 60 Å. In someembodiments, the second metal layer 208 comprises at least one oftantalum or nitride. Turning to FIG. 5, a layer of metal plug materialis formed over the second metal layer 208. In some embodiments, thelayer of metal plug material comprises copper. In some embodiments,portions of the metal plug material, such as portions that are above atop surface of the first metal layer 204, are removed, such as bychemical mechanical planarization (CMP), such that the firstinterconnect metal plug 210 a remains in the first opening 206 a, thesecond interconnect metal plug 210 b remains in the second opening 206 band a third interconnect metal plug 210 c remains in the third opening206 c. In some embodiments, portions of the second metal layer 208, suchas portions that are above the top surface of the first metal layer 204,are removed, such as by CMP, such that the first interconnect secondmetal layer 208 a remains in the first opening 206 a, the secondinterconnect second metal layer 208 b remains in the second opening 206b and a third interconnect second metal layer 208 c remains in the thirdopening 206 c. In some embodiments, the first interconnect second metallayer 208 a surrounds the bottom surface 211 c and sidewalls 211 a, 211b of the first interconnect metal plug 210 a. In some embodiments, thesecond interconnect second metal layer 208 b surrounds the bottomsurface 213 c and sidewalls 213 a, 213 b of the second interconnectmetal plug 210 b. In some embodiments, the third interconnect secondmetal layer 208 c surrounds a bottom surface 215 c and sidewalls 215 a,215 b of the third interconnect metal plug 210 c. Turning to FIG. 6, thefirst barrier cap 212 a is formed over the first interconnect metal plug210 a, the second barrier cap 212 b is formed over the secondinterconnect metal plug 210 b and a third barrier cap 212 c is formedover the third interconnect metal plug 210 c. In some embodiments, atleast one of the first barrier cap 212 a, the second barrier cap 212 bor the third barrier cap 212 c comprises at least one of cobalt orruthenium.

Turning to 106 of the method 100, as illustrated in FIG. 7, a firstdielectric layer 214 is formed over the first metal layer 204, the firstinterconnect 228 a, the second interconnect 228 b and the thirdinterconnect 228 c, according to some embodiments. In some embodiments,the first dielectric layer 214 comprises at least one of a highdielectric constant material, a medium dielectric constant material or alow dielectric constant material. In some embodiments, the firstdielectric layer 214 comprises at least one of an oxide or a nitride. Insome embodiments, the first dielectric layer 214 is formed bydeposition. In some embodiments, a photoresist is formed and patternedsuch that portions of the photoresist 216 a, 216 b remain on a secondportion 214 b 1, 214 b 2 of the first dielectric layer 214 and over asecond top portion 221 a, 221 b of the top surface of the dielectric202, where there are multiple instances of the photoresist 216, thesecond portion 214 b and the second top portion 221. In someembodiments, a first portion 214 a of the first dielectric layer 214 isover a first portion 204 d 1, 204 d 2, 204 d 3, and 204 d 4 of the firstmetal layer 204, where there are multiple instances of the first portion204 d of the first metal layer 204, and over the first interconnect 228a, the second interconnect 228 b, and the third interconnect 228 c. Insome embodiments, the first portion 204 d 1, 204 d 2, 204 d 3, and 204 d4 of the first metal layer 204 is over a first top portion 222 a, 222 b,222 c or 222 d of the top surface of the dielectric 202, where there aremultiple instances of the first top portion 222 of the dielectric 202.

Turning to 108 of the method 100, as illustrated in FIG. 8, a first etchis performed to remove the first portion 214 a of the first dielectriclayer 214 from over the first interconnect 228 a, the secondinterconnect 228 b and the third interconnect 228 c and to remove thefirst portion 204 d 1, 204 d 2, 204 d 3, and 204 d 4 of the first metallayer 204 from over the first top portion 222 a, 222 b, 222 c or 222 dof the top surface of the dielectric 202, such that a first metal layerfirst portion 204 a, a first metal layer second portion 204 b and afirst metal layer third portion 204 c remain, according to someembodiments. In some embodiments, the removal of the first portion 204 d1, 204 d 2, 204 d 3, and 204 d 4 of the first metal layer 204 exposesthe first top portion 222 a, 222 b, 222 c or 222 d of the top surface ofthe dielectric 202. In some embodiments, the photoresist 216 a, 216 b isremoved, such that the second portion 214 b 1, 214 b 2 of the firstdielectric layer 214 remains over the second top portion 221 a, 221 b ofthe top surface of the dielectric 202, and in contact with a secondportion 204 e 1, 204 e 2 of the first metal layer 204, where there aremultiple instance of the second portion 204 e of the first metal layer204. In some embodiments, the first etch removes the first portion 204 d1, 204 d 2, 204 d 3, 204 d 4 of the first metal layer 204, such that atleast one of the first metal layer first portion 204 a, the first metallayer second portion 204 b or the first metal layer third portion 204 chas a top surface that is even or flush with the top surface of thedielectric 202.

Turning to 110 of the method 100, as illustrated in FIG. 9, a secondetch is performed to form the first air gap 220 a on the first side 223a of the first metal layer first portion 204 a, the second air gap 220 bon the second side 223 b of the first metal layer first portion 204 a, athird air gap 220 c on a first side 227 a of the first metal layer thirdportion 204 c, and a fourth air gap 220 d on a second side 227 b of thefirst metal layer third portion 204 c, according to some embodiments. Insome embodiments, the second etch comprises performing at least one of adry etch or a wet etch. In some embodiments, the second portion 204 e 1,204 e 2 of the first metal layer 204 serves as an etch stop layer. Insome embodiments, the second air gap 220 b is on the first side 225 a ofthe first metal layer second portion 204 b. In some embodiments, thethird air gap 220 c is on the second side 225 b of the first metal layersecond portion 204 b. In some embodiments, the second etch exposesportions of first sidewalls 204 a 1, 204 a 2 of the first metal layerfirst portion 204 a, second sidewalls 204 b 1, 204 b 2 of the firstmetal layer second portion 204 b, and third sidewalls 204 c 1, 204 c 2of the first metal layer third portion 204 c. In some embodiments, thesecond etch removes the second portion 214 b 1, 214 b 2 of the firstdielectric layer 214 to expose the second portion 204 e 1, 204 e 2 ofthe first metal layer 204.

Turning to 112 of the method 100, as illustrated in FIG. 10, a thirdetch is performed to remove the first sidewalls 204 a 1, 204 a 2 of thefirst metal layer first portion 204 a, such that the first bottomportion 204 a 3 remains under the first interconnect 228 a, to removethe second sidewalls 204 b 1, 204 b 2 of the first metal layer secondportion 204 b, such that the second bottom portion 204 b 3 remain underthe second interconnect 228 b and to remove the third sidewalls 204 c 1,204 c 2 of the first metal layer third portion 204 c, such that a thirdbottom portion 204 c 3 remains under the third interconnect 228 c. Insome embodiments, the third etch comprises a selective etch, where theetchant is selective for the first metal layer 204. In some embodiments,the first air gap 220 a is defined between the first side 223 a of thefirst interconnect 228 a and the first sidewall 202 a of the dielectric202. In some embodiments, the second air gap 220 b is defined betweenthe second side 223 b of the first interconnect 228 a and the first side225 a of the second interconnect 228 b. In some embodiments, the thirdair gap 220 c is defined between the second side 225 b of the secondinterconnect 228 b and the first side 227 a of the third interconnect228 c. In some embodiments, the fourth air gap 220 d is defined betweenthe second side 227 b of the third interconnect 228 c and a secondsidewall 202 b of the dielectric 202. In some embodiments, the firstbottom portion width 232 a of the first bottom portion 204 a 3 issubstantially equal to the first interconnect width 234 a of the firstinterconnect 228 a. In some embodiments, the second bottom portion width232 b of the second bottom portion 204 b 3 is substantially equal to thesecond interconnect width 234 b of the second interconnect 228 b. Insome embodiments, a third bottom portion width 232 c of the third bottomportion 204 c 3 is substantially equal to a third interconnect width 234c of the third interconnect 228 c. In some embodiments, the firstinterconnect first bottom void 230 a 1 and the first interconnect secondbottom void 230 a 2 are formed by the removal of the first sidewalls 204a 1, 204 a 2 of the first metal layer first portion 204 a. In someembodiments, the second interconnect first bottom void 230 b 1 and thesecond interconnect second bottom void 230 b 2 are formed by the removalof the second sidewalls 204 b 1, 204 b 2 of the first metal layer secondportion 204 b. In some embodiments, a third interconnect first bottomvoid 230 c 1 and a third interconnect second bottom void 230 c 2 areformed by the removal of the third sidewalls 204 c 1, 204 c 2 of thefirst metal layer third portion 204 c. In some embodiments, the firstinterconnect first bottom void 230 a 1 is defined between the firstbottom sidewall 203 a 1 of the first bottom portion 204 a 3 and thefirst interconnect first void sidewall 202 a 1 of the dielectric 202. Insome embodiments, the first interconnect second bottom void 230 a 2 isdefined between the second bottom sidewall 203 a 2 of the first bottomportion 204 a 3 and the first interconnect second void sidewall 202 a 2of the dielectric 202. In some embodiments, the second interconnectfirst bottom void 230 b 1 is defined between the first bottom sidewall203 b 1 of the second bottom portion 204 b 3 and the second interconnectfirst void sidewall 202 b 1 of the dielectric 202. In some embodiments,the second interconnect second bottom void 230 b 2 is defined betweenthe second bottom sidewall 203 b 2 of the second bottom portion 204 b 3and the second interconnect second void sidewall 202 b 2 of thedielectric 202. In some embodiments, the third interconnect first bottomvoid 230 c 1 is defined between a first bottom sidewall 203 c 1 of thethird bottom portion 204 c 3 and a third interconnect first voidsidewall 202 c 1 of the dielectric 202. In some embodiments, the thirdinterconnect second bottom void 230 c 2 is defined between a secondbottom sidewall 203 c 2 of the third bottom portion 204 c 3 and a thirdinterconnect second void sidewall 202 c 2 of the dielectric 202.

Turning to 114 of the method 100, as illustrated in FIG. 10, theprotective barrier 218 is formed over the second top portion 221 a, 221b of the top surface of the dielectric 202, the first interconnect 228a, the second interconnect 228 b and the third interconnect 228 c. Insome embodiments, the protective barrier 218 is formed as a thin film.In some embodiments, the protective barrier 218 has a step coveragebetween about 50% to about 100%. In some embodiments, the protectivebarrier 218 is formed by at least one of a spin on technique, asputtering technique, ALD, PVD or CVD. In some embodiments, theprotective barrier 218 comprises dielectric material, such as a lowdielectric constant material. In some embodiments, the protectivebarrier 218 comprises at least one of an oxide or a nitride.Alternatively or additionally, the protective barrier 218 includesanother dielectric material, according to some embodiments. In someembodiments, the protective barrier 218 has a thickness between about500 Å to about 1500 Å. In some embodiments, the protective barrier 218is in direct physical contact with the second top portion 221 a, 221 bof the top surface of the dielectric 202. In some embodiments, theinterconnect metal plug 210 surrounded by the second metal 208 hasgreater protection and thus less is less susceptible to damage than aninterconnect metal plug that is not surrounded by a second metal layer.In some embodiments, the semiconductor arrangement 200 where theprotective barrier 218 is in direct physical contact with the dielectric202 has a reduced parasitic capacitance as compared to a semiconductorarrangement that does not have a protective barrier in direct physicalcontact with a dielectric. In some embodiments, reduced parasiticcapacitance reduces an RC delay, such that a semiconductor arrangementwith reduced parasitic capacitance has a reduced RC delay.

According to some embodiments, a method of forming a semiconductorarrangement comprises forming a first metal layer in a first opening ofa dielectric, a second opening of the dielectric and over thedielectric, the first metal layer comprising titanium nitride. Accordingto some embodiments, the method of forming a semiconductor arrangementcomprises forming a first interconnect over the first metal layer in thefirst opening, forming a second interconnect over the first metal layerin the second opening and forming a first dielectric layer over thefirst metal layer, the first interconnect and the second interconnect.According to some embodiments, the method of forming a semiconductorarrangement comprises performing a first etch to remove a first portionof the first dielectric layer over the first interconnect, the secondinterconnect and a first portion of the first metal layer and to removethe first portion of the first metal layer from a first top portion ofthe top surface of the dielectric, such that a first metal layer firstportion remains in the first opening and a first metal layer secondportion remains in the second opening. According to some embodiments,the method of forming a semiconductor arrangement comprises performing asecond etch to form a first air gap on first side of the first metallayer first portion and to form a second air gap on a second side of thefirst metal layer first portion, such that the second air gap is betweenthe first metal layer first portion and the first metal layer secondportion. According to some embodiments, the method of forming asemiconductor arrangement comprises performing a third etch to removefirst sidewalls of the first metal layer first portion, such that afirst bottom portion of the first metal layer remains under the firstinterconnect, and to remove second sidewalls of the first metal layersecond portion, such that a second bottom portion of the first metallayer remains under the second interconnect. According to someembodiments, the method of forming a semiconductor arrangement comprisesforming a protective barrier over the first interconnect and the secondinterconnect.

According to some embodiments, a semiconductor arrangement comprises afirst interconnect adjacent a second interconnect, the firstinterconnect over a first bottom portion of a first metal layercomprising titanium nitride. In some embodiments, the first bottomportion is in contact with a dielectric. In some embodiments, the firstinterconnect comprises a first interconnect metal plug, a firstinterconnect second metal layer and a first barrier cap, the firstbarrier cap over a top surface of the first interconnect metal plug andthe first interconnect second metal layer surrounding a bottom surfaceand sidewalls of the first interconnect metal plug. In some embodiments,a protective barrier is over the first interconnect and the secondinterconnect, where a first air gap is defined between a first side ofthe first interconnect and a first sidewall of the dielectric and asecond air gap is defined between a second side of the firstinterconnect and a first side of the second interconnect.

According to some embodiments, a method of forming a semiconductorarrangement comprises forming a first metal layer in a first opening ofa dielectric, a second opening of the dielectric and over thedielectric, the first metal layer comprising titanium nitride. Accordingto some embodiments, the method of forming a semiconductor arrangementcomprises forming a first interconnect over the first metal layer in thefirst opening, forming a second interconnect over the first metal layerin the second opening and forming a first dielectric layer over thefirst metal layer, the first interconnect and the second interconnect.According to some embodiments, the method of forming a semiconductorarrangement comprises performing a first etch to remove a first portionof the first dielectric layer over the first interconnect, the secondinterconnect and a first portion of the first metal layer and to removethe first portion of the first metal layer from a first top portion ofthe top surface of the dielectric, such that a first metal layer firstportion remains in the first opening and a first metal layer secondportion remains in the second opening. According to some embodiments,the method of forming a semiconductor arrangement comprises performing asecond etch to form a first air gap on first side of the first metallayer first portion and to form a second air gap on a second side of thefirst metal layer first portion, such that the second air gap is betweenthe first metal layer first portion and the first metal layer secondportion. According to some embodiments, the method of forming asemiconductor arrangement comprises performing a third etch to removefirst sidewalls of the first metal layer first portion, such that afirst bottom portion of the first metal layer remains under the firstinterconnect, and to remove second sidewalls of the first metal layersecond portion, such that a second bottom portion of the first metallayer remains under the second interconnect. According to someembodiments, the method of forming a semiconductor arrangement comprisesdepositing a low dielectric constant material onto the firstinterconnect, the second interconnect and a second top portion of thetop surface of the dielectric to form a protective barrier over thefirst interconnect, the second interconnect and the second top portion,where the protective barrier is in direct physical contact with thesecond top portion.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

Various operations of embodiments are provided herein. The order inwhich some or all of the operations are described should not beconstrued to imply that these operations are necessarily orderdependent. Alternative ordering will be appreciated having the benefitof this description. Further, it will be understood that not alloperations are necessarily present in each embodiment provided herein.Also, it will be understood that not all operations are necessary insome embodiments.

It will be appreciated that layers, features, elements, etc. depictedherein are illustrated with particular dimensions relative to oneanother, such as structural dimensions or orientations, for example, forpurposes of simplicity and ease of understanding and that actualdimensions of the same differ substantially from that illustratedherein, in some embodiments. Additionally, a variety of techniques existfor forming the layers features, elements, etc. mentioned herein, suchas etching techniques, implanting techniques, doping techniques, spin-ontechniques, sputtering techniques such as magnetron or ion beamsputtering, growth techniques, such as thermal growth or depositiontechniques such as chemical vapor deposition (CVD), physical vapordeposition (PVD), plasma enhanced chemical vapor deposition (PECVD), oratomic layer deposition (ALD), for example.

Moreover, “exemplary” is used herein to mean serving as an example,instance, illustration, etc., and not necessarily as advantageous. Asused in this application, “or” is intended to mean an inclusive “or”rather than an exclusive “or”. In addition, “a” and “an” as used in thisapplication and the appended claims are generally be construed to mean“one or more” unless specified otherwise or clear from context to bedirected to a singular form. Also, at least one of A and B and/or thelike generally means A or B or both A and B. Furthermore, to the extentthat “includes”, “having”, “has”, “with”, or variants thereof are used,such terms are intended to be inclusive in a manner similar to the term“comprising”. Also, unless specified otherwise, “first,” “second,” orthe like are not intended to imply a temporal aspect, a spatial aspect,an ordering, etc. Rather, such terms are merely used as identifiers,names, etc. for features, elements, items, etc. For example, a firstelement and a second element generally correspond to element A andelement B or two different or two identical elements or the sameelement.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure comprises all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A method of forming a semiconductor arrangement,comprising: forming a first metal layer in a first opening of adielectric, a second opening of the dielectric and over the dielectric,the first metal layer comprising titanium nitride; forming a firstinterconnect over the first metal layer in the first opening; forming asecond interconnect over the first metal layer in the second opening;forming a first dielectric layer over the first metal layer, the firstinterconnect and the second interconnect; performing a first etch toremove a first portion of the first dielectric layer over the firstinterconnect, the second interconnect and a first portion of the firstmetal layer and to remove the first portion of the first metal layerfrom a first top portion of the top surface of the dielectric, such thata first metal layer first portion remains in the first opening and afirst metal layer second portion remains in the second opening;performing a second etch to form a first air gap on first side of thefirst metal layer first portion and to form a second air gap on a secondside of the first metal layer first portion, such that the second airgap is between the first metal layer first portion and the first metallayer second portion; performing a third etch to remove first sidewallsof the first metal layer first portion, such that a first bottom portionof the first metal layer remains under the first interconnect, and toremove second sidewalls of the first metal layer second portion, suchthat a second bottom portion of the first metal layer remains under thesecond interconnect; and forming a protective barrier over the firstinterconnect and the second interconnect.
 2. The method of claim 1, theforming a first interconnect comprising: forming a first interconnectsecond metal layer over the first metal layer in the first opening;forming a first interconnect metal plug over the first interconnectsecond metal layer; and forming a first barrier cap over the firstinterconnect metal plug.
 3. The method of claim 2, the forming a secondinterconnect comprising: forming a second interconnect second metallayer over the first metal layer in the second opening; forming a secondinterconnect metal plug over the second interconnect second metal layer;and forming a second barrier cap over the second interconnect metalplug.
 4. The method of claim 3, at least one of: the forming a firstinterconnect second metal layer comprising depositing at least one oftantalum or nitride; or the forming a second interconnect second metallayer comprising depositing at least one of tantalum or nitride.
 5. Themethod of claim 3, at least one of: the forming a first interconnectmetal plug comprising depositing copper; or the forming a secondinterconnect metal plug comprising depositing copper.
 6. The method ofclaim 3, at least one of: the forming a first barrier cap comprisingdepositing at least one of cobalt or ruthenium; or the forming a secondbarrier cap comprising depositing at least one of cobalt or ruthenium.7. The method of claim 1, the performing a second etch comprisingperforming at least one of a dry etch or a wet etch where a secondportion of the first metal layer serves as an etch stop layer.
 8. Themethod of claim 1, the performing a first etch comprising forming aphotoresist over a second portion of the first metal layer.
 9. Themethod of claim 1, the forming a protective barrier comprisingdepositing a low dielectric constant material onto the firstinterconnect, the second interconnect and a second top portion of thetop surface of the dielectric.
 10. A semiconductor arrangement,comprising: a first interconnect adjacent a second interconnect, thefirst interconnect over a first bottom portion of a first metal layercomprising titanium nitride, the first bottom portion in contact with adielectric, the first interconnect comprising a first interconnect metalplug, a first interconnect second metal layer and a first barrier cap,the first barrier cap over a top surface of the first interconnect metalplug and the first interconnect second metal layer surrounding a bottomsurface and sidewalls of the first interconnect metal plug; and aprotective barrier over the first interconnect and the secondinterconnect, where a first air gap is defined between a first side ofthe first interconnect and a first sidewall of the dielectric and asecond air gap is defined between a second side of the firstinterconnect and a first side of the second interconnect.
 11. Thesemiconductor arrangement of claim 10, the second interconnect over asecond bottom portion of the first metal layer comprising titaniumnitride, the second bottom portion in contact with the dielectric, thesecond interconnect comprising a second interconnect metal plug, asecond interconnect second metal layer and a second barrier cap, thesecond barrier cap over a top surface of the second interconnect metalplug and the second interconnect second metal layer surrounding a bottomsurface and sidewalls of the second interconnect metal plug.
 12. Thesemiconductor arrangement of claim 11, at least one of: the firstinterconnect second metal layer comprising at least one of tantalum ornitride; or the second interconnect second metal layer comprising atleast one of tantalum or nitride.
 13. The semiconductor arrangement ofclaim 11, at least one of: the first interconnect metal plug comprisingcopper; or the second interconnect metal plug comprising copper.
 14. Thesemiconductor arrangement of claim 11, at least one of: the firstbarrier cap comprising at least one of cobalt or ruthenium; or thesecond barrier cap comprising at least one of cobalt or ruthenium. 15.The semiconductor arrangement of claim 10, a first bottom portion widthof the first bottom portion substantially equal to a first interconnectwidth of the first interconnect.
 16. The semiconductor arrangement ofclaim 10, a first interconnect first bottom void defined between a firstbottom sidewall of the first bottom portion and a first interconnectfirst void sidewall of the dielectric.
 17. The semiconductor arrangementof claim 10, the protective barrier in direct physical contact with asecond top portion of a top surface of the dielectric.
 18. A method offorming a semiconductor arrangement comprising: forming a first metallayer in a first opening of a dielectric, a second opening of thedielectric and over the dielectric, the first metal layer comprisingtitanium nitride; forming a first interconnect over the first metallayer in the first opening; forming a second interconnect over the firstmetal layer in the second opening; forming a first dielectric layer overthe first metal layer, the first interconnect and the secondinterconnect; performing a first etch to remove a first portion of thefirst dielectric layer over the first interconnect, the secondinterconnect and over a first portion of the first metal layer and toremove the first portion of the first metal layer from a first topportion of the top surface of the dielectric, to form a first metallayer first portion in the first opening and a first metal layer secondportion in the second opening; performing a second etch to form a firstair gap on first side of the first metal layer first portion and to forma second air gap on a second side of the first metal layer firstportion, such that the second air gap is between the first metal layerfirst portion and the first metal layer second portion; performing athird etch to remove sidewalls of the first metal layer first portion,such that a first bottom portion of the first metal layer remains underthe first interconnect, and to remove sidewalls of the first metal layersecond portion, such that a second bottom portion of the first metallayer remains under the second interconnect; and depositing a lowdielectric constant material onto the first interconnect, the secondinterconnect and a second top portion of the top surface of thedielectric to form a protective barrier over the first interconnect, thesecond interconnect and the second top portion, where the protectivebarrier is in direct physical contact with the second top portion. 19.The method of claim 18, at least one of: the forming a firstinterconnect comprising: forming a first interconnect second metal layerover the first metal layer in the first opening; forming a firstinterconnect metal plug over the first interconnect second metal layer;and forming a first barrier cap over the first interconnect metal plug,or the forming a second interconnect comprising: forming a secondinterconnect second metal layer over the first metal layer in the secondopening; forming a second interconnect metal plug over the secondinterconnect second metal layer; and forming a second barrier cap overthe second interconnect metal plug.
 20. The method of claim 18, theperforming a second etch comprising performing at least one of a dryetch or a wet etch where a second portion of the first metal layerserves as an etch stop layer.